806909781 has 16 divisors (see below), whose sum is σ = 1081967040. Its totient is φ = 534906240.

The previous prime is 806909737. The next prime is 806909797. The reversal of 806909781 is 187909608.

It is a happy number.

It is not a de Polignac number, because 806909781 - 2¹⁵ = 806877013 is a prime.

It is a super-2 number, since 2×806909781² = 1302206789346935922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 806909781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (806709781) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 468001 + ... + 469721.

It is an arithmetic number, because the mean of its divisors is an integer number (67622940).

Almost surely, 2^806909781 is an apocalyptic number.

It is an amenable number.

806909781 is a deficient number, since it is larger than the sum of its proper divisors (275057259).

806909781 is a wasteful number, since it uses less digits than its factorization.

806909781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2516.

The product of its (nonzero) digits is 217728, while the sum is 48.

The square root of 806909781 is about 28406.1574486941. The cubic root of 806909781 is about 930.9828054001.

The spelling of 806909781 in words is "eight hundred six million, nine hundred nine thousand, seven hundred eighty-one".